I understand your perspective, but their is another perspective also with much truth.
The French Catholic church had their own military/police force that was actually murdering unarmed peaceful Buddhist monks.
And since it was Diem’s brother heading the Catholic Church, it spread to the government too.
Buddhists were considered second class and not able to get government jobs. They were suppressed, and as such turned to Ho to try and get out of the suppression. They drove them to communism.
I had relatives there in the 1950’s and early 1960’s as advisors.
Well, your relatives’ memories are different than mine. My experience with the Buddhists were just as much against the communists as anyone else during the war. The Vietcong murdered Buddhist village chiefs as readily as they did the Catholics.
The enemy pushed atheism and believers in the Vietcong/NVA were suppressed and the Buddhists suffered as much as anyone.
When Diem was killed, most of the Buddhist opposition lost steam and the government’s forces contained as many or more soldiers as any other religious group.
Ho Chi Minh was evil - and when he finally died, the North Vietnamese finally stopped torturing our POWs and allowed them to congregate.
They would not have won if we hadn’t have left them: between MacNamara’s idiocy and the useful idiots at home, we wasted our opportunity and South Vietnam’s freedom.